The invention is related to the field of machine cooling fans, and in particular, to a modular on-line replaceable cooling fan system for computer systems.
Statement of the Problem
Electric fans are used extensively to cool electronic equipment, such as computers. This is important for efficient operation and prevention of damage to heat-sensitive electronic components. Various structures and systems are known for cooling computers. One known system, used in server applications, mounts individual fans internally of the housing. In these systems, the power circuit for each fan is connected to the power circuit of the computer to obtain the necessary working voltage. These internally-mounted fan systems are typically constructed with a light-emitting diode to indicate the operability status of each individual fan. A concern with these systems is that a failure of a fan requires the power circuit for the computer to be turned off for maintenance of the failed fan. Further, the diodes are placed internally of the server such that the status of the fans cannot be determined without removing the product housing.
A known solution for these problems is the use of externally mounted fans. Externally mounted fans typically require a separate mounting frame attached to the outside of a system cabinet and electromagnetic interference (EMI) gaskets to protect against unwanted EMI.
A concern with externally mounted fan systems is that the separate mounting frames and EMI gaskets reduce the airflow perforation area available for cooling. For example, U.S. Pat. No. 6,213,819 B1 (""819), and U.S. Pat. No. 6,236,564 B1 (""564) disclose a detachable fan rack for housing a fan having a separate mounting frame for the fans. For example, the mounting frames of the ""819 and the ""564 patents cover potential ventilation perforation area thereby blocking airflow. Further, for these externally mounted fan systems, electrical connection for each fan is either mounted directly to the carrier, or it is attached to the carrier via a cable assembly. Thus, the separate mounting frame and manipulation by a user of electrical connections complicate utilization of these fan systems, especially when redundancy and on-line replaceability are important.
Thus, a need exists for a fan cooling system that allows for on-line replacement of individual fan units and maximizes the ventilation area in the airflow pathway between the system component, such as a computer server, and the fan unit(s).
It is an object of the present invention to provide a fan cooling system for an electrical component, such as a server, that enables individual fan units to be detached without cutting off power supply for the server. It is a further object of the present invention to maximize use of the ventilation area for such a modular fan cooling system. It is yet another object of the present invention to provide an easily accessible indication of an individual fan units operability status.
The present invention helps to solve some of these problems by providing a fan cooling system having an array of fan units detachably mounted to a mounting surface of the component. A cooling fan units are provided for use with an electrical component presenting a cooling airflow to and from the enclosure of the electrical component. Each fan unit includes a fan assembly, a fan housing, and structure for mounting the unit to the component. An electric fan is provided having fan blades operable to create airflow by rotating in a path having an outer diameter. The fan housing is a box shaped housing presenting a square shaped open face and having a mutually opposed wall with openings to permit fan induced airflow through said housing and face openings. A square shaped fan wall structure is provided presenting a centrally located circular opening having a diameter outside of which are presented corner regions. The diameter of the circular opening of the wall structure is slightly greater than the outer diameter of the fan blades. The fan is affixed to the wall structure to form a fan assembly. The fan is positioned in axial alignment with the wall structure circular opening to permit fan induced airflow therethrough. The fan assembly is secured within the housing at a position that is recessed inwardly from the square shaped open face. The housing includes structure for releasably fastening the housing to the electrical component so that the open face of the housing abuts the fan mounting surface and encloses a region of airflow apertures thereon. A corner regional portion of said apertures is defined as those in longitudinal alignment with the corner regions of the fan assembly wall structure. The fan assembly induced airflow between the fan assembly and the corner region apertures of the component mounting structure is unrestricted by intervening structure, thus maximizing ventilation air flow.
Alternatively, a finger guard having an array air flow apertures may be positioned at the open face of the housing which also presents corner region apertures to improve airflow between the fan assembly and the corresponding corner region apertures located in the component mounting plate.
Each fan unit further includes an electrical connector integral with the housing for detachably connecting a fan unit with a power supply and a light emitting diode mounted to the housing for indicating operability of the fan. The electrical connector is configured to be mateably received with a connector formed in the component to provide power to the individual units.
Other advantages and components of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, which constitute a part of this specification and wherein are set forth exemplary embodiments of the present invention to illustrate various objects and features thereof.